KR20190120224A - Composition for dust containment and containment of radioactive combustion products - Google Patents

Abstract

The present invention relates to means for protecting the environment from the consequences of fire comprising radioactive elements. Compositions for dust suppression and containment of radioactive combustion products after fire extinguishing comprising radioactive elements comprise anionic, nonionic and amphoteric surfactants as surfactants and have the following compositional ratios: 3.0 to 7.0% by weight Polyvinyl alcohol aqueous solution (based on dry weight fraction); 0.1 to 0.3% by weight of plasticizer; 11.0-29.0 weight% of a surfactant; Remaining water. The present invention can implement the containment of dust suppression and radioactive combustion products formed on surfaces that may include high temperature conditions after fire extinguishing.

Description

Composition for dust containment and containment of radioactive combustion products

FIELD OF THE INVENTION The present invention relates to means for protecting the environment from radioactive contamination, and more particularly, to polymer compositions for containment based on dust suppression and aqueous solutions of polyvinyl alcohol.

In a radioactive accident involving fire, radioactive combustion products form on the surfaces and contaminants such as radioactive dust spread from the surfaces to the surrounding environment.

Fire-extinguishing agents are known which comprise a homogeneous aqueous dispersion of fine carbonate materials, which may further comprise additives for forming gels and foams. See Russian Patent No. 2414273, IPC A62D 1/00, 2011/03/20. Upon application of the medicament, the layer of the medicament immediately extinguishes the fire, but no polymer containment coating is formed on the surface that prevents secondary radioactive contamination.

Methods of preventing surface radioactive contamination are known, which is intended for decommissioning of nuclear power plants. In the implementation of the method, a foam comprising 5% polyvinyl alcohol, 1% sodium tripolyphosphate and 1% sulfonol is contaminated by radioactive material through a foam generator and subjected to containment. Applies to See Russian Patent No. 2194321, IPC G21F 9/28, G21F 9/34, 2002/12/10. After spontaneous decomposition of the foam, a homogeneous containment coating foam is formed on the surface, which significantly reduces contamination that requires removal. One factor that hinders the use of such foams is that they are not designed to be applied to surfaces that are covered with slowly burning embers or ash, and under such conditions they do not form a continuous coating.

The same properties of 0.01 to 25% based on the total mass of the solution and air bubbles dispersed in a foam-forming aqueous solution containing 0.1 to 7 moles of one or more decontamination, cleaning and / or degreasers per liter of solution Stabilized foams for decontamination, cleaning and / or oil removal are known which consist of solid particles having or mixtures of solid particles having different properties and exhibit foam-forming properties. See Russian Patent No. 2470068, IPC C11D 3/02, C11D 3/37, C11D 17/00, G21F 9/00, 2012/12/20. Such foams cannot be used for dust containment and containment of radioactive combustion products after extinguishing fires complicated by radiation factors.

It is known to prevent the generation and spread of radioactive contaminants during the demolition of buildings, mainly in the decommissioning of nuclear facilities, which includes 7-10% film-forming polyvinyl alcohol, 1-10% foam former OP-10, and the remaining amount. Use foam containing water. The composition prevents the generation and diffusion of radioactive contaminants by filling the foam inside and outside the structure before contaminants are produced. The foam layer prevents dust from spreading to the environment by forming a containment film. See Russian Patent No. 2263984, IPC G21F 9/28, B08B 15/00, 2005/11/10. The composition is recognized as a prototype.

One of the disadvantages of the basic form is that it does not form a continuous coating on the surface covered with ash.

It is an object of the present invention and its technical result to provide a composition for extinguishing a fire comprising radioactive factors, and then containing dust suppression and containment of the radioactive combustion product.

The composition for dust suppression and radioactive combustion product containment proposed in the present invention prevents dust-like contaminants from spreading after the ingot and ash are cooled, so that dust suppression and containment operations on a hot surface after a fire are prevented. Makes it possible to perform. The composition of the present invention ensures high foaming and uniform wetting of the surfaces by the composition foam. In addition, particles from the upper layer of ash are absorbed into the bubble walls and begin to actively move by the effect of alternating forces, attracting more and more ash particles. As a result, a continuous coating is formed on the ingot and ash, and the top layer of ash is drawn into the coating.

The above technical results indicate that the compositions of the present invention for suppressing dust suppression and radioactive combustion products after extinguishing fires complicated by radioactive elements are anionic, nonionic and acting as aqueous polyvinyl alcohol solutions, plasticizers and surfactants. Including surfactants which are mixtures of amphoteric surfactants, this is achieved by the fact that they have the following weight percent component ratios:

Polyvinyl alcohol aqueous solution (as weight ratio of the dry matter) 3.0-7.0

Plasticizer 0.1-0.3

Surfactants 11.0-29.0

water Remaining amount.

Polyvinyl alcohol aqueous solution is used as the film-forming agent.

Glycerin is used as a plasticizer.

The surfactant is a mixture of anionic, nonionic and amphoteric surfactants in the following weight percent ratios:

Anionic Surfactants-Alkylbenzene Sulfonate Sulfonol P   1.0-3.0

Nonionic Surfactants-Cocamidopropyl Dimethylamine Oxide

OXI SAA AP.30   8.0-22.0

Amphoteric Surfactants-Cocamidopropyl Betaine SAA AP.45   2.0-4.0.

List of technical documents for the components of the composition of the present invention:

1.polyvinyl alcohol GOST 10779-78;

2. Glycerin GOST 6259-96;

3. sulfonol P TU 2481-002-40245042-98;

4. OXI SAA AP. 30 TU 2482-007-04706205-2006;

5.BETA SAA AP.45 TU 2480-002-04706205-2004.

The composition proposed in the present invention is prepared by mixing the above components, the qualitative and quantitative composition of which is shown in Table 1.

Example

Of composition Production Example

The composition is prepared by dissolving a polymer film-forming polyvinyl alcohol in water at 60-80 ° C. (for example, in an electric pot of the KPE-60 brand) for 30 minutes. After cooling, the composition is added with stirring glycerin, sulfonol P, OXI SAA AP.30, and BETA SAA AP.45. After adding each component, it is stirred for 5 minutes.

The test results are shown in Table 2.

The viscosity of the composition was measured according to GOST 9070-75.

The period during which the coating retains its protective properties is based on the SPbSIT (TU) of St. Petersburg State Institute of Technology (TU) developed according to GOST R 51037-97, GOST R 50773-95, GOST 4.54-79, and GOST R 19465-74. Was measured according to the MI IRRT-04-2014 procedure. Samples contaminated with radionuclides were measured by recording α- and β-radiation using a UMF 2000 radiometer. The composition was applied to radiation contaminated samples. After drying, 24 hours; The level of radioactive contamination on the outer surface of the coating under test was measured by wiping with swabs at 15, 30, 60, 120, and 180 days intervals.

The shape of the coating on an ingot with ash was visually determined based on the presence of a continuous coating.

The diameter and duration of the bubbles were 1 × 10 ⁻⁵ to 1 × 10 ⁻⁷ m ³ Pa / at a gas flow rate of 3 mm ³ / s, 4 atm on a diffuse reference leak sample SOP DK% -1. It was measured according to the equipment integrated control method with the sensitivity range of the leak detection means of s.

Foam collapse start and end times were visually measured by observing and recording the time of the events.

The foam expansion ratio was determined by the ratio of the foam volume to the volume of the composition solution obtained after foam syneresis.

The degree of lump formation was determined according to the MI IRRT-05-2014 procedure of SPbSIT (TU) developed in accordance with GOST R 51037-97, GOST 4.54-79, and GOST R 19465-74. Cohesiveness was measured by the following method: The sample dust fraction of particles having a diameter exceeding a threshold after the application of the composition on the dust-forming surface was measured by mass ratio. The maximum particle size of 100 µm was used as the threshold. The mass ratio of the sample dust fraction is expressed as a percentage of the total amount of sample dust. After applying the composition on the dust-forming surface, the mass of the aggregated fraction and the ratio of the aggregated fraction to the original dry weight were calculated.

Analysis

As shown in Table 1 and Table 2, Examples 1 to 3, when the weight ratio of the dried product of the film-forming polyvinyl alcohol is in the range of 3.0 to 7.1%, the composition covers the ingot and uniformly soaks in the upper layer of ash. For example to form a continuous coating. In terms of the range of use, the coating satisfies the GOST R 51037-97 requirement-which provides protective properties for more than 180 days.

When the content of glycerin plasticizer is in the range of 0.1 to 0.3%, the composition has stable foaming properties while having high values in terms of bubble duration, foam expansion ratio, and cohesion.

When the content of SAA sulfonol P is in the range of 1.0-3.0%, the dry composition forms a continuous coating and maintains protective properties for the required duration of time.

When the content of SAA OXI SAA AP.30 is in the range of 8.0 to 22.0%, the applied composition does not "sink" into the ash layer and forms a continuous coating with stable foam forming properties.

When the content of SAA BETA SAA AP.45 is in the range of 2.0% to 4.0%, the composition has stable wetting properties, uniformly covering the ingot and permeating the ash layer.

Examples of use of compositions having a quantitative composition different from that claimed in claims 4-13

When the weight fraction of the dry matter of the film-forming polyvinyl alcohol is less than 3%, no coating is formed.

If the weight fraction of the dried product of the film-forming polyvinyl alcohol exceeds 7%, foam formation is slowed due to an increase in solution viscosity, and the protective properties of the formed coating are not maintained for a sufficient time.

When the content of glycerin plasticizer is less than 0.1%, the bubble duration is reduced because of the low number of ash particles drawn into the foam, and also the time for the coating to provide protection.

If the content of glycerin plasticizer exceeds 0.3%, the foam formation rate is reduced, and the combustion product is inhomogeneously penetrated, which shortens the time for the coating to provide protection.

When the content of SAA sulfonol P is less than 0.2%, the time for the coating formed by the composition to provide protection is shortened.

If the content of SAA sulfonol P exceeds 3.0%, the bubble size increases, creating voids inside the dry coating. That is, the coating is not continuous. In addition, the time for which the coating provides protection is drastically shortened.

When the content of SAA OXI SAA AP.30 is less than 8.0%, there is not enough time for the formed coating to provide protection.

If the content of SAA OXI SAA AP.30 exceeds 22.0%, foam formation is maintained at the same level; Therefore, there is no reason to consume more material for economic reasons.

When the content of SAA BETA SAA AP.45 is less than 2.0%, the time for the coating formed by the composition to provide protection is shortened.

If the content of SAA BETA SAA AP.45 exceeds 4.0%, the foam retains the same wetting properties; Therefore, there is no reason to consume more material for economic reasons.

The basic composition (Example 14), when applied to the combustion product, “sinks” into the upper ash layer. Thus, the surface cannot be uniformly wet to form a uniform coating.

The test results show that the composition proposed in the present invention is designed to meet the target and meets all registration criteria according to the regulations applied.

TABLE 1 Qualitative and quantitative composition of the composition of the present invention

TABLE 2 Dust Suppression and Containment Properties of the Compositions of the Present Invention

Claims (6)

Compositions for extinguishing fires comprising radioactive elements and for containment of dust and containment of radioactive combustion products, comprising aqueous polyvinyl alcohol, plasticizers, and surfactants, including anionic, nonionic and amphoteric surfactants as surfactants A composition comprising a mixture of and having the following weight percent component ratios:
Polyvinyl alcohol aqueous solution (as weight fraction of dried product) 3.0 to 7.0
Plasticizer 0.1 ~ 0.3
Surfactant 11.0 ~ 29.0
Water level. The method of claim 1,
Glycerin is used as a plasticizer in the composition of 0.1 to 0.3% by weight. The method of claim 1,
Anionic, nonionic and amphoteric surfactant mixtures are used in an amount of 11.0 to 29.0% by weight as the surfactant. The method of claim 3,
1.0 to 3.0% by weight of anionic surfactant sulfonol P is mixed with other substances and used as a surfactant. The method of claim 3,
8.0-22.0 wt% nonionic surfactant OXI SAA AP.30 is mixed with other materials and used as a surfactant. The method of claim 3,
A composition characterized in that from 2.0 to 4.0% by weight of amphoteric surfactant BETA SAA AP.45 is mixed with other substances and used as surfactant.